Intermittent movement for motion picture apparatus



NOV. 19, 1940. J A MAURER, JR 2 221418 INTERMITTENT MOVEMENT FOR MOTIONPICTURE APPARATUS Filed June 4, 1938 3 Sheets-Sheet 1 FIG. 1

QT) 24 n i T3 A .9 FIG.3

W INVENTOR. 32 1 23 J. A. MAURER, JR

INTERMITTENT MOVEMENT FOR MOTION PICTURE APPARATUS 3 Sheets-Sheet 2Filed June 4, 1938 FIG. 5

W INVENTD Nov. 19, 1940. 2,222,418

INTERMITTENT MOVEMENT FOR MOTION PICTURE APPARATUS J. A, MAURER, JR

Filed June 4, 1938 3 Sheets-Sheet 3 as as \a \e he I7 20 a5 22 a1INVENTOR.

Patented Nov. 19, 1949 UNITED STATES PATENT OFFICE INTERMITTENT MOVEMENTFOR MOTION PICTURE APPARATUS York Application June 4, 1938, Serial No.211,862

7 Claims.

This invention relates to film pull-down mechanisms or intermittentmovements for motion picture apparatus such as motion picture cameras.

More especially it relates to intermittent movements in which a clawperiodically engages successive film perforations and so pullsdown oneframe of the film at a time, whereas a pilot or registry pin may holdthe film definitely in posi- 10 tion during the periods of its dwellwhen the exposure takes place, likewise by engaging successive filmperforations.

It is one object ofthe invention to provide an intermittent movement ofthis type which is not 10 only eflicient in action, but extremely simpleand easy to manufacture.

Another object of the invention is to provide an intermittent movementwhich is as noiseless as possible in operation, even at very highspeeds.

* This is particularly important in sound picture work.

. Another object of the invention is to provide an intermittent movementwherein mechanical wear is reduced to a minimum, and which may be 25operated over long periods of time without loss of M adjustment.

According to the invention these objects are substantially achieved byreducing the ope parts of the intermittent movement connections to aminimum number.

Other objects and advantages of the will be apparent from the followingwhen read in connection with the ac drawings in which:

" Fig. 1 is a perspective view of the apparatus with a cover plateremoved,

Fig. 2 is a sectional view thereof, Figs. 3, 4 and 5 are perspectivetain parts used in the apparatus,

40 Fig. 6 is a perspective view of the apparatus shown in Fig. l buthaving a double claw, a double registry pin, and certain additionalopenings,

Fig. 7 is a perspective view of certain parts used in the apparatus ofFig. 6,

45 Fig. 8 is a diagram showing the movements executed by the parts ofthe intermittent movement, and

Fig. 9 is a perspective view of a modification thereof.

views of cer- 5 Referring to'Figs. 1 to 5 inclusive, the apparatusincludes an aperture plate l0, having a filmsupporting surface H, withan aperture l2, through which the film may be exposed during the periodsof its dwell as it is intermittently ad-v 55 vanced along the surfaceII. Lens and shutter mechanism of standard type may be provided in frontof aperture i2, and other parts oi the camera, such as the rear closingmember of the film gate, the feed sprocket, driving motor or likeactuating means, film magazine, may sirni- 5 larly be of standardconstruction and therefore are not shown.

A supporting block .14 is fastened to the aperture plate ill at rightangles, and has journaled in it a shaft i5 to which may be keyed asuitable 10 driving member, such as the helical gear 30, for receivingdriving torque from the camera-actuating mechanism. A stud or pin I6 iseccentrically mounted in the end of shaft l5, which terminates justbelow the face of block M. An arm or lever H has at a point intermediateits ends a bushing l8, which fits the pin l6. This lever l'l moves in arecess Iii in block l4,and extends in a direction perpendicularly to thesurface ii. At its front it extends beyond the film path through asuitable opening l3 in the aperture plate in. At this end the lever llcarries a claw H! which err-- gages the film for pull-down action. Clawl9 en the film from its front side, that is, from side which faces theaperture plate it,

s the intermittent movement proper lo n the rear side, that is, on thatside of the ich faces away from the apertu Wieve this the lever I! maybe 0 provide claw i9 integrally with "evil in Fig. 3.

The lever l1 oscillates at its rear end around a pivot supported by asliding plate 20. Tot at end a hole 21 may be provided the rearend oflever I7, and a stud 22 may be mounted on the plate 20, as shown by wayof example in Figs. 1 to 4. Alternatively, the stud 22 may be mounted onthe rear end of lever 11, and the hole 2i may be provided in the plate2|]. The sliding plate 20 has a preferably circular opening 23 into orthrough which the pin 16 and the bushing l8 may extend, this opening 23being large enough to allow the pin l6 and bushing 18 to travel freelytherein when the shaft i5 is rotated at a uniform rate by thecamera-actuating mechanism through the driving member 30. The slidingplate 20 may advantageously be of substantial width and length relativeto the other parts, and particularly it may have relatively longrectilinear bearing surfaces which can readily be machined and fittedwith extreme accuracy. The sliding plate 20 is set in a guide, channelon the face of block fl having opposite parallel edges 24, 25, which arerelatively long and support and guide the sliding plate 20 forreciprocating motion toitself, as

ward and away from the film. By its pivoted connection to sliding plate20, the rear end of lever I1 is constrained to reciprocate in a straightline toward and away from the film.

Extending from the front end of sliding plate 20, and having in front ofthe pivot 2I, 22, a pilot or registry pin 26 is provided toengage thefilm at appropriate times, as hereinafter explained. The aperture plateID has a small opening 2'! through which the pin 26 may pass when it isin film-engaging position, while the opening I3 in the aperture plateIll is elongated so as to allow the claw I9 to move convenientlytherein.

A cover or retaining plate 28, shown in Figs. 2 and 5, may be fastenedby any suitable means to the face of block I4 in order to hold thesliding plate 26 in its channel and atthe same to protect the mechanismfrom dust and dirt. The: retaining plate 28, however, may be omitted ifthe sliding plate 26 is held otherwise in its channel,- for example, bydovetailing it to block It.

While the apparatus is of particular advantage with film having a singlerow of perforations along one side, as in the case of 16 mm. sound film,it may also be used succcessfully for films having two rows ofperforations. In such case, satisfactory resultsmay often be had with asingle claw and registry pin as shown in Figs. 1 to 4. But the lever I1and the plate 26 may also carry a double claw and a double registry pin36, and

the aperture plate I0 may be provided with additional openings 31 and.38 so that claw 35 may move in openings I3 and 31, and registry pin 36may pass through openings 21 and 38, as shown by way of example in Figs.6 and '7.

, A diagrammatic representation of the. movementsexecuted by theeccentric pin I6, the claw I9, and the registry pin 26, is shown in Fig.8. The line A-B is the path of reciprocation of the pivot 2|, 22, aroundwhich the lever I'I, carrying the claw I9 at its front end, oscillatesat its rear end, and which is supported by the sliding plate 26,carrying the registry pin 26. The circle C is the path of the eccentricpin I6. The approximately elliptical line D is the path of the tip ofclaw I9, every point on which pursues a path similar to D. The line E-Fis the path of reciprocation of the registry pin 26, and the dotted lineGH shows the plane of the film. v

When the eccentric pin I6 is in the position I nearest the film, the tipof claw I9 is in the position K, and the end of the registry pin 26 isin the position E. As the cycle of movement starts in -the directionindicated by the arrows 46 and 4|, the eccentric pin I6 moves. to theposition L, at which stage the tip of claw I9 is in its highest positionat M; At the same time the pivot 2I, 22, and the end of the registry pin26 are at S and Trespectively. v

At this stage in the cycle the registry pin 26 is just leaving thev filmperforation, and the pull, down action commences. When the eccentric pinI6 reaches the position N, the'tip f claw I9 is at O, the end of theregistry pin 26 is at F, and the pivot 2i, 22, is at B. The eccentricpin I6 continues its motion to the point P, at which stage the tipofclaw I9 is at its lowest position R, and the pivot 2i, 22, and the endof the registry pin 26 are again at points S and T, respectively.Registry pin 26 is just entering the nextperforation in the film.

At this point the pull-down action ceases, and

' the period of dwell begins. This period of dwell extends over theremainder of the cycle, during which the eccentric pin I6 passes through1.

and back to L, the registry pin 26 being continuously engaged with thefilm, and the claw I9 being out of active engagement with it.

It will be noted that the points M and R, which mark the highest andlowest positions of the tip of claw I9 on its approximately ellipticalpath D, are to the right of the plane of the film GH. Thus the tip ofclaw I9 is well entered through the perforation of the film before itbegins to pull the film down, and likewise it is not completelywithdrawn from the film at the time when the pull-down action ceases. Itis therefore impossible for the movement to skip a perforation hole inpulling down the film. The tip of claw I9 is rounded and tapered in sucha manner that actual pull-down contact between the claw I9 and the filmbegins when the claw I9 is at point M, and ceases when it reaches pointR.

Furthermore, because claw I9 engages the film from its front side, thepull-down action occurs when eccentric pin I6 is moving on that half ofcircle C which is away fromv the plane of the film GH and toward thepivot 2 I, 22. For this reason the pull-down action takes place duringless than 180 of rotation of the eccentric pin I6. The angle of rotationduring which the actual pull-down action takes place is shown by thedotted lines 42 and 43, and, as is evident from the geometricalrelations in Fig. 8, this angle is less than 180 by the amountof theangle a, which is formed by the tangents through the points L, M, and P,R, on circle C and. "ellipse D, respectively.

As shown in detail in Figs. 3 and 4, eccentric pin I6, claw I9, andregistry pin 26, may be made integral with their carriers, viz., shaftI5, lever I1, and slide 20. Thus the intermittent movement according tothe invention comprises to each other at only two pointsthe shaft I5through the eccentric pin 'I6'and the bushing I8 to the lever I1, andthe lever I1 through hole 2I and stud 22 to the slide 20. Because themotion at these points is a purely rotary motion of round pin parts inround bushings which can be made to fit with great accuracy and freedomfrom backlash, the action of the movement is almost perfectly noiseless,even at very high speeds. For the same reason the mechanical wear isvery slight, so that the movement may be operated over long periodsoftime without loss of adjustment.

It has been found that by virtue of the essentially sinusoidal nature ofthe motion imparted by the eccentric pin I6, the deceleration of theclaw I9 is such as to bring the film uniformly to a position of completerest when the pulldown action ceases, and that in order to hold the filmin proper position during the period of its dwell, it is only necessaryto provide slight pressure on the film as by the pressure platecustomarily employed in film gate constructions. Hence, in appropriatecases the registry pin 26 may be omitted as indicated by the dotted line32, 32, in Fig. 4.

Although in the presently preferred embodiments of the invention, asshown in Figs. 1 to 8, the eccentric pin- I6 engages the lever. I 'I ata point intermediate its'ends, the invention may be carried out also byhaving the pin I6 engage the lever at its rear end, as shown, by way ofexample, in Fig. 5.

In this case thepull-down action occurs when the eccentric pin I6 ismoving on the front half of its cycle of movement, which is indicated bythe dotted circle 60 in'Fig. 9, the direction of movement being shown bythe arrow 6|. There fore the claw 5| carried by the lever 50 must nowengage the film from its rear side, and to achieve this the front end oflever 58 may be suitably rounded and tapered, as shown in Fig. 9. Thepath of claw 5| is indicated by the "ellipse 62, and its direction ofmovement by the arrow 63.

Furthermore, the lever 50 must now be mounted at a point intermediateits ends on the pivot mounted on slide .52. This may be achieved in anyof the ways discussed hereinabove in connection with Figs. 1 to 4, forexample by mounting a stud 54 on the lever 50 and providing acorresponding hole (not shown in Fig. 9) in the slide 52, or in anyother suitable way.

On the other hand, if a registry pin is to cooperate with the claw 5| inthis case, it must engage the film from its front side. It isnecessary,,therefore, that registry pin 53 extend beyond the film pathand that its end be bent back, as shown in Fig. 9; registry pin 53 beingcarried again by the sliding plate 52 in front of the pivot 54.

Finally, in case the sliding plate 52 extends to or beyond the rear endof lever 50, as shown, a preferably circular opening 55 must now beprovided in it to the rear of pivot 54.

Although its action is described herein as pull down, the intermittentmovement need not advance the film in an actually downward direction,but may pull orpush it in any direction consonant with the design of theapparatus in which it isused.

The above description is merely to illustrate certain embodiments of theinvention, which is not limited to the specific arrangements shown butis of the scope of the appended claims.

What is claimed is:

v1. Intermittent movement for motion picture apparatus comprising a clawadapted to engage the film from its front side; a lever carrying at itsfront end said claw; an eccentric engaging said lever at a point betweenits ends; a pivot, said lever oscillating at its rear end around saidpivot; a plate having rectilinear bearing surfaces and supporting saidpivot; and means guiding said plate along said rectilinear bearingsurfaces for sliding motion toward and away from said film.

2. Intermittent movement for motion picture apparatus comprising a clawadapted to engage the film from its rear side; a lever carrying at itsfront end said claw; an eccentric engaging said lever at its rear end; apivot, said lever oscillating at a point between its ends around saidpivot; a plate having rectilinear .bearing surfaces and supporting saidpivot; and means guiding said plate along said rectilinear bearingsurfaces for sliding motion toward and away from said film.

3. Intermittent movement for motion picture apparatus comprising asupporting block having a guide channel; a sliding plate in saidchannel; a pivot on the rear end of said plate-and a registry pin on thefront end thereof, said registry pin being adapted to engage the filmfrom its rear side; a lever mounted at its rear end on said pivot andhaving a claw on its front end, said claw being adapted to engage thefilm from its front side; and an eccentric mounted for rotation in saidblock and connected to said lever intermediate the ends thereof to drivesaid lever and reciprocate said plate.

4. Intermittent movement for motion picture apparatus comprising aslide; a pivot and a registry pin on said slide, said registry pin beingin front of said pivot and adapted to engage the film from its rearside; means providing a guide for said slide; a lever mounted at itsrear end on said pivot and having a claw on its front end, said clawbeing adapted to engage the film from its front side; and an eccentricconnected to said lever intermediate the ends thereof to drive saidlever and reciprocate said slide.

5. Intermittent movement for motion picture apparatus comprising asupporting block having a guide channel; a sliding plate in saidchannel; a pivot on the rear end of said plate and a registry pin on thefront end thereof, said registry pin being adapted to engage the filmfrom its front side; a lever mounted intermediate its ends on said pivotand having a claw on its front end, said claw being adapted to engagethe film from its rear side; and an eccentric mounted for rotation insaid block and connected to said lever at the rear end thereof to drivesaid lever and reciprocate said plate..

6. Intermittent movement for motion picture apparatus comprisin a slide;a pivot and a registry pin on said slide,'said registry pin being infront of said pivot and adapted to engage the film from its front side;means providing a guide for said slide; a lever mounted intermediate itsends on said pivot and having a claw on its front end, said claw beingadapted to engage the film from its rear side; and an eccentricconnected to said lever at the rear end thereof to drive said lever andreciprocate said slide.

7. Intermittent movement for motion picture apparatus comprising aslide; a pivot and a' registry pin on said slide, said registry pinbeing in front of said pivot; means providing a guide for said slide; alever mounted at one point on said pivot and having a claw on its frontend; an eccentric connected to said lever at another point thereof todrive said lever and reciprocate said slide, one of said points being atthe rear end and the other intermediate the ends of said lever; and saidclaw and said registry pin being adapted to engage the film fromopposite sides.

JOHN A.- MZAURER, JR.

CERTIFICATE '01 conmzcnon. 1 Patent 10. 2,222,h1 1 November 19, 191;,0.

JOHN A. mums, J'R.- It is hereby certified-that error appears in theprinted specification of the above numbered patent requiring correctionas follows; Page 2, first column, 'lineB', for the word "havirig" read--hence--; page 5, first column, line 8, for "lever 58' read "lever-50--; end that the said Letters Patent shouldhe read with thiscorrection therein that the same may conform to the record of the casein the Patent Office.

Signed and. sealed this IIth day of February, A. D. 19141.

Henry Van Arsdale, Acting Commissioner of Patents.

